System and methods for raised touch screens

ABSTRACT

A touch sensitive display assembly includes a touch screen and a button array. The touch screen is configured to display one or more input keys. The button array includes one or more buttons corresponding to the one or more input keys. The button array is formed by a substrate attached to a button membrane thereby creating a set of button cavities corresponding to the input keys. The button cavities are configured to be inflated and deflated by a pump coupled to a fluid reservoir. The cavities can be inflated/deflated together, in subsets, and/or individually. In some embodiments, the button array is sandwiched between a touch sensing layer and a display of the touch screen. In other embodiments, the button array can be located either above or below the touch screen.

BACKGROUND OF THE INVENTION

This invention relates generally to touch sensitive displays. More particularly, this invention relates to cost effective systems and methods for selectively raising portions of touch sensitive displays.

Touch sensitive displays, e.g., touch screens, are very useful in applications where a user can input commands and data directly on a display. Common applications for touch screens include consumer products such as cellular telephones and user interfaces for industrial process control. Depending on their specific applications, these touch sensitive displays are commonly used in devices ranging from small handheld PDAs to large pieces of industrial equipment.

While it is convenient to be able to input and output data to and from the user on the same display, unlike a dedicated input device such as a keypad with discrete well-defined keys, most touch sensitive displays are generally flat. As a result, touch sensitive screens do not provide any tactile guidance for control “button(s)”. Instead, touch sensitive displays rely on visual guidance for user input.

Hence a serious drawback of touch sensitive displays is its inherent difficulty to input data accurately because adjacent buttons are not distinguishable by feel. Wrongly entered key strokes are common and the user is forced to keep his or her eyes on the display. The lack of tactile guidance is especially critical in industrial settings where potentially dangerous machines and parts are in constant motion such as an automobile assembly line, and also when operating the controls of a moving vehicle such as making a cellular telephone call while driving.

It is therefore apparent that an urgent need exists for an improved touch sensitive display which provides tactile guidance to the user that is easy to manufacture, easy to retrofit, shock resistant, impact resistant, remains compact and portable, cost effective, and durable.

SUMMARY OF THE INVENTION

To achieve the foregoing and in accordance with the present invention, systems and methods for tactile guidance in touch sensitive screens are provided. Such touch screens can be operated very effectively and more safely without substantially increasing cost.

In one embodiment of the invention, a touch sensitive display assembly includes a touch screen and a button array. The touch screen is configured to display one or more input keys. The button array includes one or more buttons corresponding to the one or more input keys. The button array is formed by a substrate attached to a button membrane thereby creating a set of button cavities corresponding to the input keys.

The button cavities are configured to be inflated and deflated by a pump coupled to a fluid reservoir. The cavities can be inflated/deflated together, in subsets, and/or individually. In some embodiments, the button array is sandwiched between a touch sensing layer and a display of the touch screen. In other embodiments, the button array can be located either above or below the touch screen.

These and other features of the present invention will be described in more detail below in the detailed description of the invention and in conjunction with the following figures.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the present invention may be more clearly ascertained, one embodiment will now be described, by way of example, with reference to the accompanying drawings, in which:

FIGS. 1A and 1B are cross-sectional views illustrating the operation of a button array in accordance with the present invention;

FIG. 2 is a cross-sectional view of one embodiment of the present invention;

FIGS. 3A, 3B and 4 are cross-sectional views of alternate embodiments of the present invention;

FIGS. 5 and 6 are top views showing a button array and an exemplary touch screen which can be combined to form an exemplary input and output (I/O) user interface suitable for telephone-based communication applications;

FIG. 7 is a block diagram illustrating one exemplary implementation of a device incorporating the touch sensitive user interface of the button array in accordance with the present invention; and

FIG. 8 is a flowchart illustrating the operation of touch screen assemblies of the present invention, including the embodiments shown in FIGS. 2, 3A, 3B and 4.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described in detail with reference to several embodiments thereof as illustrated in the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without some or all of these specific details. In other instances, well known process steps and/or structures have not been described in detail in order to not unnecessarily obscure the present invention. The features and advantages of the present invention may be better understood with reference to the drawings and discussions that follow.

FIGS. 1A and 1B are cross-sectional views illustrating the operation of a button array 100, useful in association with a touch sensitive display, in accordance with the present invention. Although only one button is shown, button array can include one or more buttons. In the following discussion and in the claims, touch sensitive display is used interchangeably with touch screen. Referring first to FIG. 1A, button array 100 includes a substrate 130 and a membrane 110 which are coupled to each other to form one or more enclosed cavities, e.g., enclosed cavity 120.

Substrate 130 can be made from a suitable optically transparent material including polymers or glass, for example, elastomers, silicon-based organic polymers such as poly-dimethylsiloxane (PDMS), thermoset plastics such as polymethyl methacrylate (PMMA), and photocurable solvent resistant elastomers such as perfluropolyethers. In some embodiments, substrate 130 is a single homogenous layer approximately 1 mm to 0.1 mm thick and can be manufactured using well-known techniques for micro-fluid arrays to create one or more cavities and/or micro channels. It is also possible to construct substrate 130 using multiple layers from the same material or from different suitable materials.

Membrane 110 can be made from a suitable optically transparent and elastic material including polymers or silicon-based elastomers such as poly-dimethylsiloxane (PDMS) or polyethylene terephthalate (PET). In some embodiments, membrane is a single homogeneous layer less than 1 mm thick (preferably 50 to 200 microns) and can be manufactured using techniques known to one skilled in the art. It is also possible to construct membrane 110 using multiple layers from the same material or from different suitable materials. Membrane 110 can be attached to substrate 130 using a suitable adhesive, ultra-sonic bonding, oxygen plasma surface treatment or any other suitable techniques known to one skilled in the art.

Enclosed cavity 120, formed between substrate 130 and membrane 110, is fluid tight and coupled via a fluid channel 140 to one or more fluid pumps (not shown in FIG. 1A). Note that the pump(s) can either be internal or external with respect to a touch screen assembly incorporating button array 100.

A suitable button fluid can be used to inflate exemplary cavity 120. To minimize optical distortion, the refractive index of the button fluid should be substantially similar to that of substrate 130 and also membrane 110. Depending on the application, suitable fluids include water and alcohols such isopropanol or methanol. It may also be possible to use an oil-based fluid such as Norland's index matching liquid (IML) 150 available from Norland Products of Cranbury, N.J.

Referring now to FIG. 1B, when button array 100 needs to be activated, i.e., raised or in other words inflated, fluid pressure inside cavity 120 is increased thereby causing membrane portion 110 a to be raised. In this example which is suitable for a handheld device, cavity 120 has a cavity diameter of approximately 5 mm and membrane 110 is approximately 100 micron thick. Conversely, when button array 100 needs to be deactivated, fluid pressure inside cavity 120 is decreased thereby causing cavity 120 to deflate and membrane portion 110 a to return to its original flat profile. It is contemplated that a button fluid pressure of approximately 0.2 psi and a button fluid displacement of about 0.03 ml should be sufficient to raise membrane (button) portion 110 a by about 1 mm.

FIG. 2 shows a cross-sectional view of one embodiment of a touch sensitive display assembly comprising button array 100 of the present invention located on top of a touch display which includes a touch sensing layer 260 and a display screen 280. In this embodiment, button array 100 includes multiple cavities 220 a, 220 b, 220 c and corresponding membrane portions 210 a, 210 b, 210 c. Button array 100 is located just above touch sensing layer 260. Although FIG. 2 shows button array 100 in contact with touch sensing layer 260, it may be possible for a gap to exist between array 100 and sensing layer 260. The gap may optionally be filled with a suitable flexible solid or fluid material.

It is also possible for display screen 280 to include sensors that provide input capability thereby eliminating the need for sensing layer 260. For example, an LCD with embedded optical sensors both touch screen and scanner functions was announced in a 2007 press release by Sharp Electronics of Japan.

FIG. 3A is a cross-sectional view of another embodiment of a touch sensitive display assembly of the present invention wherein a touch sensing layer 360 and a display screen 380 of the touch sensitive display are separated. Button array 100 includes multiple cavities 320 a, 320 b, 320 c and corresponding membrane portions 310 a, 310 b, 310 c. In this embodiment, button array 100 is sandwiched between a flexible touch sensing layer 360 and display screen 380. As a result, raising membrane portions 310 a, 310 b, 310 c results in the raising of sensing layer portions 360 a, 360 b, 360 c, respectively.

FIG. 3B is a cross-sectional view of a variation of the touch sensitive display assembly of FIG. 3A wherein two or more cavities are inflated, a contiguous portion of touch sensing layer 360 is raised. In this embodiment, button array 100 is also sandwiched between touch sensing layer 360 and display screen 380. When cavities 320 d, 320 e are inflated, corresponding membrane portions 310 d, 310 e are raised, thereby causing the raising of sensing layer portions 360 d, 360 e. In addition, raising membrane portions 310 d, 310 e also results in the raising of touch sensing layer portion 360 f located between sensing layer portions 360 d, 360 e.

FIG. 4 is a cross-sectional view illustrating yet another embodiment of a touch sensitive display assembly wherein the entire touch screen is made from flexible material(s). Hence, the touch screen includes a flexible touch sensing layer 460 and a flexible display screen 480. Button array 100 includes one or more cavities 420 a, 420 b, 420 c and corresponding membrane portions 410 a, 410 b, 410 c. In this embodiment, button array 100 is located below display screen 480.

As discussed above, button array 100 and sensing layer 460 may be attached directly to each other or array 100 and layer 460 may be operatively coupled to each other via a suitable intermediate solid or fluid material.

FIGS. 5 and 6 are top views showing a button array 500 and an exemplary touch screen 600 which can be combined to form an exemplary input and output (I/O) user interface suitable for telecommunication applications. While the following description uses the 14-key telephone-based keypad of FIG. 5, the present invention is also applicable to many other non-telecommunication applications.

Button array 500 includes cavities 520 a, 520 b, 520 c, 520 d, 520 e, 520 f, 520 g, 520 h, 520 k, 520 m, 520 n, 520 p, 520 q, 520 r, while touch screen 600 is configured to able to display a set of corresponding input keys 620 a, 620 b, 620 c, 620 d, 620 e, 620 f, 620 g, 620 h, 620 k, 620 m, 620 n, 620 p, 620 q, 620 r. In this example, cavities 520 a, 520 b, 520 c . . . 520 r are overlaid on corresponding input keys 620 a, 620 b, 620 c . . . 620 r, using the exemplary techniques described above for the embodiments of FIGS. 2, 3A, 3B, 4.

As shown in FIG. 5, button array 500 is coupled to fluid pumps 572, 576. A fluid reservoir 574 is located between fluid pumps 572, 576. Suitable commercially available fluid pumps include pump #MDP2205 from ThinXXs Microtechnology AG of Zweibrucken, Germany and also pump #mp5 from Bartels Mikrotechnik GmbH of Dortmund, Germany.

Button array 500 is coupled to inflating fluid pump 572 and deflating fluid pump 576 via inlet fluid channel system 592 and outlet fluid channel system 596, respectively. In this example, fluid channel systems 592, 596 vary in width, i.e., wider in width nearer pumps 572, 576, in order to ensure fluid pressure and flow uniformity, in a manner similar to a human circulatory system.

Although the techniques discussed are applicable to many embodiments of the present invention, including the embodiments of FIGS. 2, 3A, 3B, 4, for this discussion, reference is made to the embodiment of FIG. 2. For ease of explanation, in the following discussion, all cavities 520 a, 520 b, 520 c . . . 520 r are inflated and deflated at the same time. Note that in some implementations, depending in the specific applications, cavities, e.g., cavities 520 a, 520 b, 520 c . . . 520 r, can be inflated and/or deflated individually, in subsets and/or as a complete set.

In this embodiment, inflating pump 572 is activated for a pre-determined period of time whenever cavities 520 a, 520 b, 520 c . . . 520 r need to be inflated. Note that deflating pump 576 remains “off” during inflation of cavities 520 a, 520 b, 520 c . . . 520 r. As a result, pump 572 is able to transfer fluid from fluid reservoir 574 to cavities 520 a, 520 b, 520 c . . . 520 r, until the required fluid pressure is accomplished. Inflating pump 572 is now deactivated, and both pumps 572, 576 are “off”. Fluid pressure is maintained in cavities 520 a, 520 b, 520 c . . . 520 r to keep them inflated.

Conversely, deflating pump 576 is activated for a pre-determined period of time whenever cavities 520 a, 520 b, 520 c . . . 520 r need to be deflated. Inflating pump 572 remains “off” during deflation of cavities 520 a, 520 b, 520 c . . . 520 r. As a result, deflating pump 576 is able to transfer fluid from cavities 520 a, 520 b, 520 c . . . 520 r back to fluid reservoir 574 to, until the required fluid pressure returns to the original value when deflating pump 576 is turned “off”.

Other pump configurations are also possible. For example, it is possible to replace pumps 572, 576 with a single bi-directional pump. It may also be possible to deflate cavities by opening value(s) to the fluid reservoir and let the fluid pressure decrease without the need for a separate deflating pump.

FIG. 7 is a block diagram illustrating one exemplary implementation of a device 700 incorporating a touch sensitive user interface in accordance with the present invention. Device 700 includes a microprocessor (CPU) 710, a button array controller 720, pump(s) 721, and button array 100. Depending on the implementation, device 700 may also include pressure sensor(s) 722 and valve(s) 723 coupled to pump(s) 720. Device 700 also includes a display controller 730 coupled to a display screen 280, and a touch screen controller 740 coupled to touch sensing layer 260.

FIG. 8 is a flowchart illustrating the operation of touch screen assemblies of the present invention, including the embodiments shown in FIGS. 2, 3A, 3B and 4. Referring to FIGS. 5 through 8, and using the embodiment of FIG. 2 as an example, in step 820, when display controller 730 causes display screen 280 to display a keypad, e.g., a telephone interface, button array controller 720 activates pump(s) 721 which causes button array 100, corresponding to the keys of keypad, to be inflated by increasing the pressure of the button fluid in cavities 220 a, 220 b, 220 c (step 830).

In step 840, touch sensing layer 260 senses the location(s) of the user's depressions on one or more of corresponding membrane portions 210 a, 210 b, 210 c of button array 100. Touch sensing layer 260 then outputs the coordinate(s) of the sensed location(s) to processor 710 via touch screen controller 740 (step 840).

If processor 710 recognizes that the sensed location(s) correspond to an “EXIT” type key, for example, a “CALL” key or an “END” key in this exemplary telecom implementation, then button array 200 is deflated (step 860). Otherwise, touch sensing layer 260 continues to sense location(s) of subsequent user depression(s) and outputting the sensed location(s) coordinates to touch screen controller 740 (repeat step 840, 850).

Many modifications and additions are contemplated within the spirit of the present invention. For example, it is possible to add distortion correction capability to display screens 280, 380, 480 for correcting any optical distortion that may be introduced by button array 100. It may also be possible to include a set of pressure sensors coupled to each of the corresponding cavities of button array 100 thereby eliminating the need for touch sensing layers 260, 360, 460.

While the present invention has been described with reference to particular embodiments, it will be understood that the embodiments are illustrative and that the inventive scope is not so limited. In addition, the various features of the present invention can be practiced alone or in combination. Alternative embodiments of the present invention will also become apparent to those having ordinary skill in the art to which the present invention pertains. Such alternate embodiments are considered to be encompassed within the spirit and scope of the present invention. Accordingly, the scope of the present invention is described by the appended claims and is supported by the foregoing description. 

1. A touch sensitive display assembly comprising: a touch screen configured to display at least one input key; and a button array operatively coupled to the touch screen, wherein the button array having at least one button corresponding to the at least one input key, the button array including: a substrate; and a button membrane attached to the substrate thereby forming at least one enclosed cavity corresponding to the at least one button, and wherein the at least one enclosed cavity is configured to be inflated and deflated.
 2. The touch sensitive display assembly of claim 1 wherein the touch screen includes a touch sensing layer and a display screen, and wherein the button array is sandwiched between the touch sensing layer and the display screen.
 3. The touch sensitive display assembly of claim 1 wherein the button array is located below the touch screen.
 4. The touch sensitive display assembly of claim 1 wherein the button array is located above the touch screen.
 5. The touch sensitive display assembly of claim 1 further comprising at least one pump configured to inflate and deflate the at least one enclosed cavity.
 6. The touch sensitive display assembly of claim 1 further comprising a reservoir coupled to the at least one pump.
 7. The touch sensitive display assembly of claim 1 further comprising a valve coupled between the at least one pump and the button array.
 8. The touch sensitive display assembly of claim 1 further comprising a second button, and wherein the at least one button and the second button are inflated and deflated separately.
 9. The touch sensitive display assembly of claim 1 further comprising a second button, and wherein the at least one button and the second button are inflated and deflated together.
 10. The touch sensitive display assembly of claim 1 further comprising at least one corresponding pressure sensor coupled to the at least one cavity, and wherein the touch screen is configured to compensate for optical distortion introduced by the button array.
 11. A button array useful in association with a touch screen configured to display at least one input key, the button array comprising: a substrate; and a membrane attached to the substrate thereby forming at least one enclosed cavity corresponding to the at least one input key of the touch screen, and wherein the at least one enclosed cavity is configured to be inflated and deflated.
 12. The button array of claim 11 wherein the touch screen includes a touch sensing layer and a display screen, and wherein the button array is configured to be sandwiched between the touch sensing layer and the display screen.
 13. The button array of claim 11 wherein the button array is configured to be located below the touch screen.
 14. The button array of claim 11 wherein the button array is configured to be located above the touch screen.
 15. The button array of claim 11 wherein the button array is configured to be operatively coupled to at least one pump configured to inflate and deflate the at least one enclosed cavity.
 16. The button array of claim 11 wherein the at least one pump is coupled to a reservoir.
 17. The button array of claim 11 wherein the button array is configured to be coupled to the at least one pump via a valve.
 18. The button array of claim 11 further comprising a second button, and wherein the at least one button and the second button are inflated and deflated separately.
 19. The button array of claim 11 further comprising a second button, and wherein the at least one button and the second button are inflated and deflated together.
 20. The button array of claim 11 wherein the at least one cavity is configured to be operatively coupled to at least one corresponding pressure sensor, and wherein the touch screen is configured to compensate for optical distortion introduced by the button array. 